Abstractions for networking code

[zyzzyxdonta]

Hermes should have an abstraction layer for HTTP request capabilities. We should aim for a more uniform interface to the network as currently both urllib3 and requests are used. The abstraction would also allow us to have a custom User-Agent header by default (https://github.com/hermes-hmc/workflow/pull/160#discussion_r1183374734) and to safely handle authorization credentials (https://github.com/hermes-hmc/workflow/pull/144#discussion_r1142219012)